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      <H1>A model from pharmacokinetics;<BR>A comparison with 
    NLME</H1><BR><BR></TD></TR>
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          <TD align=middle><FONT face="Arial, Helvetica" color=white><B>ADMB 
            Files</B></FONT> </TD></TR>
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                <TD>Code: <A 
                  href="pheno.tpl">pheno.tpl</A><BR>Data: 
                  <A 
                  href="pheno.dat">pheno.dat</A><BR>Initial 
                  values: <A 
                  href="pheno.pin">pheno.pin</A><!--<BR>All 
                  required files (DOS): <A 
                  href="http://otter-rsch.com/admbre/examples/pheno/pheno.zip">pheno.zip</A><BR>All 
                  required files (linux): <A 
                  href="http://otter-rsch.com/admbre/examples/pheno/pheno.tar.gz">pheno.tar.gz</A><BR>-->Expected Results: 
                  <A 
                  href="pheno-expected-results.par">pheno.par</A><BR></FONT></TD></TR></TBODY></TABLE></TD></TR></TBODY></TABLE><BR>
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                <TD>In a <A 
                  href="http://otter-rsch.com/admbre/examples/admb_tutorial.html">DOS</A> 
                  window<BR>Under <A 
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          <TD align=middle><FONT face="Arial, Helvetica" 
            color=white><B>Results: Computation times</B></FONT> </TD></TR>
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                <TD>ADMB-RE: 5 seconds.<BR><TT>nlme</TT>: 7 
                seconds<BR></FONT></TD></TR></TBODY></TABLE></TD></TR></TBODY></TABLE><BR>
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                  home</A> <BR><A href="http://otter-rsch.com/">Otter 
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      <H3><STRONG>Model description</STRONG></H3><A 
      href="http://otter-rsch.com/admbre/examples/citations.html#pinh:bate:2000">Pinheiro 
      &amp; Bates (2000, Ch. 6.4)</A> fitted a so-called 'one-compartment open 
      model' to a dataset known as the 'phenopharbital data'. A patient is given 
      a dose <EM>D</EM> at time <EM>t</EM><SUB>d</SUB>, giving rise to a 
      phenopharbital concentration <EM>c<SUB>t</SUB></EM> at a later time 
      <EM>t</EM>: <BR>
      <DIV align=center><EM>c<SUB>t</SUB></EM> = <EM>D/V</EM> 
      exp[-<EM>Cl/V</EM>(<EM>t</EM>-<EM>t</EM><SUB>d</SUB>)], </DIV><BR>where 
      <EM>V</EM> and <EM>Cl</EM> are parameters (the so-called 'Volume of 
      concentration' and the 'Clearance', respectively). Doses given at 
      different time points contribute additively to <EM>c<SUB>t</SUB></EM>. 
      <BR><A 
      href="http://otter-rsch.com/admbre/examples/citations.html#pinh:bate:2000">Pinheiro 
      &amp; Bates (2000)</A> fitted a model with a linear predictor (and a 
      log-link) for each of the paramere <EM>V</EM> and <EM>Cl</EM>. Each of the 
      linear predictors contained one covariate <EM>Wt</EM> and one random 
      effect. A full description of the model can be found here: <A 
      href="http://otter-rsch.com/admbre/examples/pheno/pheno.pdf">pheno.pdf</A> 

      <H3><STRONG>Results</STRONG></H3>The results produced by ADMB-RE and 
      <TT>nlme</TT> are rather similar. The small difference is caused by the 
      fact that the two methods use different approximations to the likelihood 
      function. (ADMB-RE uses the Laplace approximation, and for <TT>nlme</TT> 
      the reader is referred to ( <A 
      href="http://otter-rsch.com/admbre/examples/citations.html#pinh:bate:2000">Pinheiro 
      &amp; Bates, 2000</A>, Ch. 7).) </TR></TBODY></TABLE></BODY></HTML>
